The invention relates to a descender used for descending a person along a rope, comprising a first fixed flange for support of a pulley and of a stud or pad separated from one another by an internal space for passage of the rope, and a second mobile flange able to occupy a separated position enabling the rope to be wound according to a first predetermined direction onto the pulley and stud in the passage space, and a closed position in which the rope is held captive in the space, movement of the second flange from the separated position to the closed position, and vice-versa, being achieved in a plane appreciably parallel to the first flange by manual action of the user.
The function of a descender must enable a user to descend along a rope of great length in complete safety. In the case of a self-jamming descender, the pulley is shaped as a mobile cam associated with an unlocking handle. If the handle is released during a descending movement, the tension on the rope urges the cam to a locking position, in which the rope is pressed by the cam against a fixed stud or stop. This results in automatic stopping of the descending movement, and the person remains attached to the rope in complete safety. Correct operation of the descender nevertheless remains dependent on a certain direction of winding of the rope on the pulley, said direction being known to all specialists and indicated on the apparatus. The risk of an incorrect direction of passage of the rope is not to be excluded when the descender is handled by novices or inexperienced users. The self-jamming effect of the rope does not occur in case of an assembly error, and this results in incorrect operation of the descender, which may have unfortunate consequences for safety.
The object of the invention consists in achieving a safety descender for a rope which does not jeopardize the life of a person when the direction of passage of the rope in the descender is incorrect.